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  1. #1
    Join Date
    Dec 2004
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    61

    Question Refrigerant Dryer Necessary?

    I recently had a new heat pump air handler (American Standard TAM7, 2 ton) installed to match a American Standard 2 ton heat pump that is about 4-5 years old. The accepted work proposal included a refrigerant dryer installed on the R-22 lines.

    There were some short cuts taken by the installers and the company owner came by a few days later to resolve them. He acknowledged his installers hadn't installed the dryer but noted the existing heat pump has one inside the unit. He told me that he could add the new one (to be installed outside of the outdoor unit) the next day as it would take some time and the refrigerant lines would need to be opened.

    I'm still waiting. Is this an important part? Over the long term, would it help prevent my new air handler from being damaged/life shortened? (I'm hoping that the indoor unit will outlast the heat pump, and at that time a 410A conversion would be needed.)

    Does the old line dryer last forever, or does it fill with moisture or whatever it is removing?

    I'm looking to know if I should ask him back to install it like he said he would. Thanks.

  2. #2
    John Culpepper's Avatar
    John Culpepper is offline CHANGE YOUR EMAIL ADDRESS Professional Member*
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    Oct 2007
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    Every time the refrigeration circuit is opened the dryer should be replaced.
    Nemo me impune lacessit.

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    Don't look down on anyone unless you're helping them up.

  3. #3
    Join Date
    Jul 2012
    Location
    Richland, WA
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    248
    Quote Originally Posted by John Culpepper View Post
    Every time the refrigeration circuit is opened the dryer should be replaced.
    Not all the time, if they pumped the heat pump down to the installation, no they don't have to replace the drier. If they didn't pump the system down, but recovered, then yes they need to replace the drier inside the heat pump.

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  4. #4
    Join Date
    Dec 2011
    Location
    Grass Lake, MI
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    The drier must be replaced if outside the unit (in the copper lines and not the unit itself if the unit was pumped down). If the system was evacuated or the old drier was ever exposed to the outside air, it must be replaced. Hold him to his word.

  5. #5
    Join Date
    Dec 2004
    Posts
    61
    Thanks for the advice! I will call them again tomorrow. The system used recovered R22 (I recall at the beginning of the job they ran the compressor for a minute or so with a valve closed and may have used a vacuum pump to empty the lines. The old air handler was ancient (old GE with lots of rust on the coil's exterior).

    Some follow up questions:
    1.) The system has been running for a few weeks since the new handler was installed. Is this a problem?
    2.) Should the new dryer be installed outside of the unit (e.g. exposed) or replace the existing dryer inside the outdoor unit?
    3.) The air handler install directions say to pressurize the system with Nitrogen to leak test after brazing the indoor coil connections. I was paying attention at various times through the install, and am pretty sure I never saw them do this or have a nitrogen tank anywhere. Is this something I should ask about?

  6. #6
    Join Date
    Jul 2012
    Location
    Richland, WA
    Posts
    248
    They pumped the system down. With what you just said, so the drier in the unit was never exposed to air.


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  7. #7
    Join Date
    Dec 2010
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    Down by the river
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    If it was pumped down...I see no need to replace the dryer.

  8. #8
    Join Date
    Dec 2011
    Location
    Grass Lake, MI
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    251
    Your system was pumped down. The drier was never exposed to the outside air. NO need to replace. You can just let it go. There is more potential for damage if they come back and open it up now.


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  9. #9
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
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    Quote Originally Posted by jpbhvac View Post
    Your system was pumped down. The drier was never exposed to the outside air. NO need to replace. You can just let it go. There is more potential for damage if they come back and open it up now.




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    X4 move forward if one is added to the outside of the unit the one inside would need removed and repiped

  10. #10
    Join Date
    Sep 2002
    Location
    Northeast Ohio
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    4,842
    If the original drier is inside the condensing unit, the only way to change it will be to recover ALL of the refrigerant, OPEN the system, CHANGE the drier and RECHARGE the unit. The old drier should not be left and an additional one installed. Given your description of how the work was performed, I would leave well enough alone here, you will be better off.
    A good HVAC tech knows how, an educated HVAC tech knows why!

    DEM


  11. #11
    Join Date
    Mar 2009
    Location
    Mount Holly, NC
    Posts
    3,120
    agreed.

    however, do you know if they pressure tested for leaks after they installed the air handler? do you know if they ran a vacuum pump for an appreciable time on the new air handler?
    I'd be concerned if they left out that step... but the internal dryer, if the original system still had a full charge of refrigerant, and has not been leaking needing recharging over the years, I'm ok with them not changing the dryer.

    however, if the owner of the company DOES come out to install a new dryer... be SURE it's either installed inside the condenser where the original one was, or they REMOVE that original one, and install the new one either near the air handler, or elsewhere in the line.
    The TRUE highest cost system is the system not installed properly...
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  12. #12
    Join Date
    Dec 2004
    Posts
    61
    UPDATE:

    The company owner just installed a filter drier himself, outside the unit. He cut into the refrigerant line and brazed in a bi-directional filter drier. I did ask about removing the old one. He said that there is no reason why the old drier would need to be removed and it would not be worthwhile to do so. The new drier is quite a bit larger than the old one mounted inside the cabinet.

    Hopefully everything is correct. There was an issue with starting the unit after the system was restarted, the outdoor unit kept cycling on a pressure switch while the gauges were still attached. Apparently the electronic expansion valve on the American Standard TAM7 remained closed after the compressor was restarted, probably because the inside unit was running and calling for cool while the vacuum pump was evacuating the line after the drier installation. After the inside unit power was recycled, everything was fine. Would this hurt the expansion valve inside?

    The unit appears to be running fine, pressures and subcooling were checked after the installation was complete.

  13. #13
    Join Date
    Sep 2002
    Location
    Northeast Ohio
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    4,842
    The old drier should have been removed. Should have left well enough alone..
    A good HVAC tech knows how, an educated HVAC tech knows why!

    DEM


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